Stock indicator



G. FOX ET AL STOCK INDICATOR May 15, 1934.

Filed Deo. 17, 1927 2 Sheets-Sheet l G. FOX EVAL May 151, 1934.

STOCK INDICATOR Filed Deo. 17, 1927 2 Sheets-Sheet 2 IIHISMSIQIIIIWI Il Patented May 15, 1934 UNITED STATES PATENT OFFICE Application December 17, 1927, Serial No. 240,917

9 Claims.

The present invention relates to improvements in stock indicators.

More particularly the present invention relates D to means for indicating the level of material with- I in a receptacle such, for example, as a blast furnace. The present invention has been illustrated and will be described with particular reference to a blast furnace, though as the description proceeds it will be clear that the invention in its v.10 broader aspects is applicable to other types of indicators.

An object of the present invention is toprovide a stock indicator which involves only relay tively simple `parts which may be readily pur- 515v chased in the open market, which is sturdy and whichY is not likely to get out of order.l l

A further object is 'to provide a stock indicator which involves' a weighted member which may be controlled by a cable, which indicator, with L a minimum of simple parts, will allow said weighted member to descend until an indication of level is had, after which the weighted member will be drawn up at once.

A further object is to provide a stock indicator f2.5 fora blast furnacer which will cooperate with the charging means for said furnace, whereby tov 'insure that the indicating means will be held in a position, while the furnace is being charged, such that danger of the indicating means being '30 buried is' avoided.

A further object is to provide a stock indicator operated by a dynamo-electric machine adapted to have bothA motoring and general functions, which stock indicator will be responsive to the 351 voltage drop set up in said vdynamo-electric machine.'

Further objectsl will appear as the description proceeds.

Referring to the drawingsy Figure 1 is a more or less diagrammatic view illustrating the principles of the present invention;y and v Figure 2 is a schematic layout of the electric circuits which may be utilized in the practice of ,i5 the present invention.

Referring iirst to Figure 1, the numeral 10 indicates a receptacle which is embodied in a blast furnace. Said blast furnace 10 is provided with the'charging bell 11, which may be controlledV by the cable 12,. vSaid cable 1271s controlled by the lever 13., said lever in Vturn being controlled by thecable 14. The cable 14 passesl over the sheave 15 and is connected to an operating member adapted to exert a downward pull upon said cable 14. The particular operating member chosen for illustration comprises the cylinder 16, adapted to have a movement of reciprocation along a vertical axis. Said cylinder is weighted by means of weight members 1'7-1'7. Disposed within the cylinder 16 is the relatively stationary 60'. piston 18, provided with the internal bore 19. Said bore 19 communicates with the pipe 20, adapted to carry liquid to said bore 19 and to deliver liquid from said bore 19. The pipe 2 0 is connected to the pump 21, which is of the 651 reversible type. The pump 21, which is illustrated as being a rotary pump, is driven by the dynamoelectric machine 22. The other side of the pump 21 is connected to the pipe 23, which leads to the lower portion of the reservoir 24. The upper 76:; portion of the reservoir 24 is connected to the pipe 20 through the pipe 25, the relief valve 26 being provided in the pipe 25. The particular operating means for exerting the pull upon the cable 14 forms no part of the present invention 75"' and need not be described in detail. Means suitable for the purpose are described and claimed in the copending application of Gordon Fox, led June 2, 1927, Serial No. 195,882, Patent No. 1,760,637. It will be sufficient to state in con- 8'0"; nection with the present application that the dynamo-electric machine 22 is adapted to operate with motoring functions to drive the pump 21 .in a direction to deliver liquid from the reservoir 24 to the pipe 20, which liquid will exert, 8'5; a lifting force upon the weightedV cylinder 16 to allow the charging bell 11 to drop by gravity, whereby to deposit its burden within the blast furnace 10. After the burden has been discharged from the charging bell 11, the cylinder will be 903 allowed to descend, forcing liquid back through the pump 21, which, being reversible, will drive the dynamo-electric machine 22 with generating' functions. The dynamo-electric machine 22 may be provided with a dynamic braking circuit, whereby to allow the bell 12 to close in a safev manner. The liquid discharged through theA pump 22 will, of course, be returned to the reservoir 24. By reason of the relief valve 2.6, the dynamo-electric machine 22 and pump 21 may 100 operate in a pumping sense to maintain Va presaA sure to hold up the cylinder 16 and to hold the charging bell 11 in open position. It may also, be desired to utilize the functions of the relief valve 26 to give a time delay for dumping of the 105 charging bell 11. Moreover, the relief valve permits holding the bell 11 open for inspection or cleaning. The movable cylinder 16 is provided with an operating member 27 adapted to control a limit switch, indicated as a whole by the numeral 28. Said limit switch 23 is provided with the normally open pole 29 and the normally closed pole 30. When the cylinder 16 is in its lowered position, as indicated in Figure l, the normally open pole 29 will be held in closed position. At this time the normally closed pole 39 will be open. When the cylinder 16 is out of its lowered position, the normally open pole 29 will be open and the normally closed pole 30 will be closed. The electrical circuits involving the poles 29 and 30 of the limit switch 28 will be referred to further hereinafter.

The numeral 31 indicates a try rod, which may be carried by any preferred guide means for constraining said try rod to move in a vertical line. Only one try rod has been illustrated, but it will be understood that a plurality of try rods may be provided at spaced regions within the blast furnace 10. The try rod 31 is connected to the cable 32, which rides upon sheaves 33-33. The other extremity of the cable 32 is connected to the grooved drum 34, which drum 34 has secured thereto the gear 35. A pinion 36 meshes with the gear 35, which pinion 36 is connected to the dynamo-electric machine 37. Also connected to the dynamo-electric machine 37 is the brake wheel 38, adapted to be controlled by the brake shoes 39. The brake shoes 39 are controlled by the shunt brake coil 40. Connected to the drum 34 is the shaft 41, which is provided with the worm 42 meshing with the worm wheel 43. Operation of the worm Wheel 43 results in the actuation of the indicator 44. By reason of the fact that the indicator 44 is connected to the try rod 31, it will be clear that said indicator 44 will show the range of movement of said try rod 31. The numeral 45 indicates a limit switch, which limit switch is provided with a pair of poles 45a and 45h. Pole 45a'l opens when the try rod 31 is at its top position. Pole 455 is open with the try rod 31 in top position but closes after said try rod is partly lowered.

Reference may'now be had to the schematic diagram shown in Figure 2. The two sides of an electric circuit are illustrated by the numerals 46-46. The dynamo-electric machine 37 is connected across said circuit through the starting resistor 47 and the contactor 48, which contactor 48 is normally open. The dynamo-electric machine 37 includes the armature 49 and the series field winding 50. Also connected across the circuit 46-46 is the shunt field winding 50A of the dynamo-electric machine 37. Also bridged across the conductors 46-46 is the shunt brake coil 40, above referred to, and the brake relay 51, which brake relay is normally open. Connected in circuit across the armature 49 and the series field winding 50 of the dynamo-electric machine 37 is the braking -resistor 52 and the back contactor 53, which back contactor 53 is connected to operate in unison with the contacter 48. Said back contactor 53 is normally closed, being closed when contactor 48 is open, and, conversely, open when contactor 48y is closed. The numeral 54 indicates a voltage drop relay having the movable element 54A, the forward contacts 55-55 and the backv contact 56. The movable element 54A is connected to the conductor 46 at the right of Figure 2. voltage drop relay coils 57 and 58. Coil 57 is bridged across the braking resistor 52. Coil 58 is connected across the conductors 46-46 in a circuit which also includes the protective resistor 59 of the voltage drop coil 54 and the start button 60, which start button is normally open. The

The relay 54 is controlled by the two coil 58 of the voltage drop relay 54 is adapted to be bridged by pole 45b of the limit switch 45. As noted above, said pole 45h is open when the try rod 31 is in top position, and closes after said try rod is partly lowered. Connected across the Acircuit which includes the coil 58 and the protective resistor 59 is a circuit includingthe contacts -55 and the coil 61 of the brake relay 51. The circuit last mentioned is closed when the movable element 54A of the voltage drop relay 54 is in bridging relationship with the contacts 55-55. Said coil 61 of the brake relay 51 is in a circuit adapted to be connected across the conductors 46--46 by the pole 45a of the limit switch 45. As noted above, said pole 45a opens when the try rod 31 is at its top position. Also adapted to be connected across the conductors 46 is a circuit including the auxiliary contact 62 of the brake relay 51 (which auxiliary contact 62 closes with said brake relay 51), the coil 63 of the contactor 48, the contact 56, and the movable element 54A of the voltage drop relay 54.

A control circuit will now be described by means of which the try rod 31 is interlocked with the charging bell 11.. By reference to Figure 1, it will be noted that when the cylinder 16 is in its lowermost position, corresponding to closed position of the charging bell 11, the normally open pole 29 of the limit switch 28 is held in closed position, whereas when the cylinder 16 has been raised above its lowermost position, said pole 29 is in open position and the pole 30 is closed.

Connected across the start button is a circuit which includes the normally open pole 29 of the limit switch 28. Said circuit also includes the relay 64, which is normally open. Connected across the conductors 46-46 is a circuit which includes the normally closedpole 30 of the limit switch 28, the operating coil 65 of the relay 64 and the auxiliary contact 66 uponV the brake relay 51. Said auxiliary contact 66 on the brake relay 51 closes when saidb-rake relay 51 opens, and, conversely, said auxiliary contact 66 opens when the brake relay 51 closes. Bridged across the normally closed pole 30 of the limit switch 28 is the auxiliary contact 67 on relay 64, which closes with said relay 64 and opens with said relay 64.

A mode of operation of the abovetdescribed em-ibodiment of the present invention is substantially as follows. With reference to the operation of the charging bell 11, it will be understood, of course, that the weighted cylinder 16 holds the charging bell 11 inclosed position, except when material is being discharged into the blast furnace 10. With the bell in closed position, material will be deposited upon said bell, and instrumentalities, not shown, will be set in operation to energize the dynamo-electric machine 22 as a motor to drive the pump 21 to force liquid from the reservoir 24 through the pipe 20 into the cylinder 16. This will lift the cylinder 16, removing the pull from the cable 14 and allowing the charging bell 11 to open. After the material is charged fromthechargingbell 11, said bell will be allowed to close.

The try rod 31-is normally held suspended at the upper limit of its travel, the brake 39 being biased to braking-position.l At this time both poles 45a and 45h of the limit switch 45 are open.

When the start button 60 is closed, circuit is completed from one conductor 46 through the coil 58 of the voltage drop relay 54 through the protective resistor 59 and start button 6o to the lll other conductor 46. Energiz'ation of theA coil 58 cames the operation of the voltage drop relay 54, bridging the contacts 55-55 This completes a holding circuit around the start button 60,. inasmuch as contacts 55-55 and the moving element of relay 54 are bridged across said start button 60. This also completes a. `circuit from` the left-hand conductor: 46 through coil 61 of the brake relay 51 to the right-hand conductor 46. Energization of the coill results in the closure of the brake relay 5l, which in turn energizes the shunt brake coil 40, releasing the brake shoes 139-39. The weight of the try rod 31 causes the armature 49 of the dynamoelectric machine 3.7 to rotate backwards; thatis; the try rod 31 overhauls the kdynamo-electric machine 37. Contacter 48 cannot closefat this time to cause the dynamo-electric machine 37 toy operate as a motor, because thevoltage drop relay 54 is in its left-hand position, open-cirouiting the operating coil 63 of said contacter 48'. `The descent of the try rod 31 is controlled by meansl of the dynamic braking circuit across the armature 49 and series field 50, which dynamic braking circuit includes the braking lresistor' 52 and the back contacter Y53 upon the contactar 48; As noted above, said back contacter 53 is closed when contactor 48 is open. After the try rod has started to descend, the pole a of the limit switch 45 closes, thereby oy-passing the moving element 54A of the voltage drop relay 54, the circuit being traced from the left-hand conductor 46 through the coil 61 of the brake relay 51 and through the pole 45a of the limit switch 45,

to the right-hand conductor 46. After a predetermined number of revolutions, which in practice may be chosen in the neighborhood of two revolutions, pole 45h closes, short-circuiting the coil 58 of the voltage drop relay 54. The voltage drop relay 54 does not open at thistime because the voltage drop across the braking resistor is suincient to cause the coil. 57 of the voltagel droprelay 54 to function and hold theY moving element 54A of the voltage drop relay 54 in engagement with the contacts -55. Assoon as the try rod 31 strikes the burden within the blast furnace 10 the speed of the armature 49 is reduced, reducing the generator voltage, which in turn reduces the voltage drop across the brakingr resistor 52, thereby reducing the current through the coil 57 of the voltage drop relay 54 to such a value as to cause the moving element 54A of said voltage drop relay to move to the right, thereby open-circuiting the contacts 55-55 and closing the normally closed contact. A circuit is now completed from the left-hand conductor 46, through the auxiliary contact 62, through coil 63 of contactor 48, through contact 56 and movable element 54A to the right-hand conductor 46. Energization of the coil 63 results in the closing of contactor 48, which action opens the back contacter 53. The dynamic braking circuit around the armature 49 is thereby broken, and power is applied to the armature 49 for motoring functions, circuit being completed through the left-hand conductor 46, series field winding 50, armature 49, starting resistor 47 and contacter 48 to the right-hand conductor 46. By reason of these motoring functions, the dynamo-electric machine 37 hoists the try' rod. tor the top of the blast furnace. In a position of the try rod near the top of the furnace (corresponding to substantially two turns of the drum before `stopping according to the example above noted) ,pole 45h of the limit switch 45 opens. This causes no changes, as the circuits affected areV opened elsewhere. The armature 49 Vhoists the try rod 31 until pole 45a of the limit switch 45 opens, which opens circuit through the brake relay coil 6l of the brake relay 51. The brake relay 51 is thereby allowed to open, which also opens the auxiliary contact 62 on said brake relay 51. Opening of the auxiliary contact 62 results in the deenergisation of coil 63 of the contacter 48, which opencircuits the dynamo-electric machine 37, causing the dynamo-electric machine to stop. Inasmuch as the brake relay is open, the shunt brake' coil 40 is deenergized. and the brake 39 is applied. The interlocking relationship between the bell operating means and the try rod operating means will now be referred to. With the bell operating cylinder 16 in its lowermost position corresponding to a closed position of the bell ll, the normally open pole 29 of the limit switch 28' is closed, but relay 64 is open. When the cylinder rises in response to energization of the motor 22, the normally closed pole 30 of the limit switch 28 is closed, which completes a circuit from the right-hand conductor 46 through said pole 30, through the coil 65 of the relay 64, through the auxiliary contact 66 on the brake relay 5l (which is closed when brake relay 5l is open) to the lefthand conductor 46. The energization of the coil 65 results in the closure of the relay 64, which' results in the closure of the auxiliary Contact 67 on said relay 64. 'Closure or" the auxiliary contact 67 by-passes the pole 30 `of the limit switch 28. When the bell cylinder 16 has gone through its cycle of movementv and has returned to its lowermost position, the normally open pole 29 of the limit switch 28 is closed. Circuit is thereby completed from the right-hand conductor 46 through the normally open pole 29 of the limit switch 28, through relay 64, through resistor'` 59 and through the operating coil 58 of the voltage drop relay 5.4 to the left-'hand conductor 46. Energization of the coil 58 causes operation of the dynamo-electricmachine 37 in the manner above described. When the brake relay 5l closes,the auxiliary contact 66 on said brake relay `51 is opened, thereby opening the circuit of the operating coil 65 of the relay 64, causing relay 64 to open. Simultaneously with the opening of relay 64, the auxiliary contact 67 opens, which puts the circuits back into the condition assumed at the beginning of this paragraph.

Y It will bev observed that the present invention provides a system in which thel stock indicator is interlocked with the charging bell operating' means of a blast furnace, in which system the weighted indicating member is allowed to descend (under the influence of the dynamic braking circuit) until it strikes the burden,l after" which the weighted indicating member is immediately lifted in response to functions of the dynamic braking circuit referred to. The present invention involves only a few simple parts, which are readily purchasable inthe open market, which are sturdy, and which are not likely to get out of order.

Though a preferred embodiment of the pres-Y ent invention has been described in detail, it be clear that many modifications will occur to those skilled in the art. It is intended to cover all such modifications as fall within the scope of the appended claims. y

What is claimed is- 1. In a level indicator, a suspended reciproca-` ble test member, an electric motor for raising said test member, said motor performing as a gen- IIS erator upon descent of said testmember, braking means for holding said test member in elevated position, electric control means ier releasing said test member to overhaul said motor whereby said motor operates as a generator, a dynamic braking circuit for said. motor, said dynamic braking Vcircuit including a resistor, a relay for controlling the connection of said motor to a source of electromotive force, said relay including a pair of operating coils, one of which is connected to be responsive to the voltage drop across said resistor, meansconnecting the other of said coils to said source of electro-motive force during the descent of said test member', and short-circuiting means for said` other coil, said short-circuiting means being responsive to movementk of said test member. Y

2. In a charging system, in combination, a receptacle, a charging bell therefor, means for operating said charging bell, a Vweighted test member suspended within said receptacle, a brake for holding said test member inraised position, brake releasing means, an electric motor for lifting said test member, limit switch means adapted to be operated by said bell operating means, and relay means for connecting said electric motor to a source of electromctive force, said relay means being conjointly responsive to said limit switch means and to said brake releasing means. l

3. In a blast furnace charging system, in combination, a charging bell, operating means therefor, a suspended reciprocable weighted test member, brake means for holding said test member in elevated position, brake releasing means, an electric motor for raising said test member, a relay for connecting said motor to a source of electromotiver force for motoring functions,. means responsive to said 'bell operating means for controlling the eifectiveness of said relay, and means responsiveto said brake releasing means for c ontrolling said relay.

4. In combination, a level indicator, a suspended reciprocable test member, an .electric motor for raising said test member, said motor performing as a generator upon descent of said test member, brake means for said motor biased to brakingrelationship with said motor, electrical control means controlling said brake means for releasing said test member, said electrical control means including a dynamic braking circuit cooperatively associated with said motor, arelay for causing the energization of said motor to return said test member to a predetermined position, said relay comprising av pair of operating coils, one of which is connectedv to be responsive to the Voltage developedby said motor while it is performing saidgenerating functions, means for connecting the other of saidl coils yto an external source of electromotive force during the descent of said test vmember andshortcircuiting means for said other coil, said shortcircuiting means being responsive to movement of said test member.

5. In a level indicator, in combination', a suspended reciprocable test member, an electric motor for lifting said test member, electrical control means for said motor, said electrical control means including means for limiting the extent which said motor may raise said test member, said electrical control means also including a switch biased to open position, means responsive to said switch for releasing said test member to operate said motor as a generator `for braking functions, and relay means for causing the energization of said motor to raise said test meinber,said relay means including a pair of operating coils, one of which is connected to be responsive to the voltage'developed by said motor while it is performing said generating functions, means for connecting the other of said coils to an external source of electromotive force during the descent of said test member and short-circuiting' means for said other coil, said shortcircuiting means being responsive to movement of said test member.

.6. In a level indicatonin combination, a suspended reciprocable test member, a dynamoelectric machine adapted to operate as a generator upon descent of the test member and as a motor vto raise said test member, hoisting mechanism for said test member, said hoisting mechanism being connected to' said dynamo-electric machine, a brake for said hoisting mechanism for holding said test member in raised'position, a starting'switchvbiased to open position, electrical control means responsive to the momentary closure vvof said starting switch for releasing said brake to permit the lowering of said test member, said electrical control means including means for causing the energization of said dynamoelectric'machine as a motor, said last mentioned means being responsive to the operation of said dynamo-electric machine as a generator and including a relay responsive to changes in the voltage drop produced by said dynamo-electric machine when operating as a generator to conneet said dynamo-electric machine to a source of electric p'owerrfor motoring functions to lift said test member, said relay including a pair of operating-coils, one 'of which is connected to be responsive to the voltage developed by said dynamo-electric machine while performing generating functions, said starting switch :being adapted to connect the other of said coils to said source of electric power, and short-circuiting means for said other coil, said short-circuiting means being responsive to movement of said test' member.

7. In a level indicator including a suspended reciprocable test member, a dynamo-electric machine adapted to operate as a generator upon descent of the test member and as 'a'mctor to raise said test member, hoisting mechanism for said test member, said hoisting mechanism being connected to said dynamo-electricmachine, a brake for holding said test member in raised position, a starting switch biased yto open position, electrical control means responsive to the momentary closure of said starting switch for releasing said brake, a relay for causing the energiza'tion of said motor to raise said test member, and a limit switch for stopping said motoring functions and setting said brake when said test member has beenraised to a predetermined position, said relay including a pair of operating coils, one of which is connectedy to be responsive to the voltage developed by said motor while it is performing said generating functions, means including said starting switch for connecting the other of said coils to said vsource ofipower the descent of said `test member, andshort-circuiting means for said otherv coil, said shortcircuiting means beingrresponsive to movement of said test member. y

8. In a level indicaton'in combination, a suspended reciproeable test member, an electric motor for raisingsaid test member, said motorV during` said motor to allow said test member to lower, brake means for holding said test member in elevated position, electric control means for releasing said brake means to cause the dropping of said test member to overhaul said motor, said motor being provided with a dynamic braking circuit, a relay for controlling the connection of said electric motor to its source of electric power, said relay being responsive to changes in the generating functions of said motor While being overliauled by said test member, said relay including a pair of operating coils, one of which is connected to be responsive to the Voltage developed by said motor while itis performing said generating functions, means including said starting switch for connecting the other of said coils to said source of electric power during the descent of said test member, and short-circuiting means for said other coil, said short-circuiting means being responsive to movement of said test member.

9. In a level indicator, a suspended reciprocable test member, an electric motor forV raising said test member, said motor performing as a generator upon descent of said test member, a brake for holding said test member in elevated position, electrical control means for releasing said brake to cause the dropping of said test member to overhaul said motor, a dynamic braking circuit for said motor including a resistor, a relay for controlling the connection of said motor to a source of electromotive force for motoring functions of said motor, said relay including a coil responsive to the voltage drop across said resistor, said relay also including a second coil, means connecting said second coil to a source of electromotive force during the descent of said test member, and short-circuiting means for said second coil, said short-circuiting means being responsive to movement of said test member.

GORDON FOX. ARTHUR J. WHITCOMB. 

